The present invention generally relates to contraception and/or sterilization, and more particularly to temporary or permanent intrafallopian contraceptive devices, delivery systems, and non-surgical methods for their deployment.
While the theoretical effectiveness of existing non-surgical contraceptive techniques, including barrier methods and hormonal therapies, is well established, the actual effectiveness of most known methods is disappointing. One reason for these disappointing results is that many of the presently available methods for inhibiting pregnancy without surgery depend upon significant user involvement. Non-compliance typically results in quite high rates of failure, and overcoming user non-compliance to improve overall efficacy has proven quite difficult.
One form of long term contraception which is less susceptible to user non-compliance is the intrauterine device (IUD). IUDs have been found to have higher rates of reliability, and are effective for a longer period of time, then most other commercially available contraceptives. Unfortunately, IUDs are also associated with serious infectious complications. For this reason, the use of IUDs within the United States has decreased dramatically. Additionally, IUDs are subject to unplanned expulsion, and are removed due to excessive pain or bleeding in a significant percentage of cases, further reducing acceptance of the IUD as a method of inhibiting pregnancy.
Commercially available options for permanent sterilization include fallopian tube ligation and vasectomy. These methods are surgical and are not available to many people in the world. It is common knowledge that fertilization occurs in the fallopian tubes where the sperm and ovum meet. Tubal ligation avoids this by surgical and complete occlusion of the fallopian tubes.
In work done in connection with the present invention, it has previously been proposed to transcervically introduce a resilient coil into a fallopian tube so as to inhibit conception. PCT patent application No. 99/15116, assigned to the present assignee (the full disclosure of which is incorporated herein by reference) describes devices which are transcervically inserted into a tubal ostium and mechanically anchored within the fallopian tube. The described devices may promote a tissue ingrowth network to provide long term conception and/or permanent sterilization without the need for surgical procedures, and should avoid the risks of increased bleeding, pain, and infection associated with intrauterine devices.
While the recently proposed intrafallopian contraceptive devices represent a significant advancement in the art, still further improvements would be desirable. In general, it would be desirable to provide improved non-surgical devices, systems, and methods for inhibiting pregnancy. It would be beneficial if these improved techniques increased the ease with which these contraceptive devices could be deployed, and if the improvements further enhanced the long term retention of the contraceptive device once it has been deployed. It would be further beneficial if these improved access and deployment techniques were suitable for a wide variety of physiological geometries, ideally without having to tailor the device, deployment system, or deployment method for specific individuals. Some or all of these advantages are provided by the devices and methods described hereinbelow.
The present invention generally provides improved contraceptive and/or sterilization methods, systems, and devices. The invention generally improves the ease, speed, and reliability with which a contraceptive device can be deployed transcervically into an ostium of a fallopian tube. In many embodiments, a distal portion of the contraceptive device will function as a guidewire, facilitating advancement of the device (and the deployment system) into the tubal ostium. Typically, a proximal portion of the device will remain covered by a deployment sheath until the device is in position. Thereafter, the sheath can be withdrawn proximally, exposing a surface which is well adapted for retaining the device within the tube and/or uterotubal junction (but which would not be ideal for facilitating advancement of the device if left unsheathed during positioning). In the exemplary embodiment, the proximal portion remains in a small profile configuration while the sheath is withdrawn proximally, and is thereafter expanded to a large profile configuration engaging the surrounding tissues. Actuation may be affected after withdrawal of the sheath by a variety of mechanisms, ideally by restraining a helical coil of the proximal portion using first and second elongate bodies. Releasing one of the bodies relative to the other can release the exposed helical coil to expand resiliently. The released helical coil can safely engage and anchor the contraceptive device within a wide variety of physiological tissue geometries. Using the distal end of the contraceptive device as a guidewire avoids the complexity of multiple step deployments (which might otherwise involve separate guidewire access, catheter access, and advancement of the device), while still providing a smooth, easily advanced outer system profile.
In a first aspect, the invention provides a contraceptive method comprising guiding a contraceptive device distally into an ostium of a fallopian tube with an exposed distal portion of the contraceptive device while a sheath covers a proximal portion of the contraceptive device. The proximal portion of the guided contraceptive device is uncovered by withdrawing a sheath proximally from the proximal portion. The uncovered contraceptive device is released so that the contraceptive device inhibits conception.
Typically, the contraceptive device comprises an axially elongate flexible structure. Advantageously, the proximal portion of this flexible structure can be supported by the surrounding sheath while the distal portion is acting as a guidewire. Often times, at least a portion of the exposed distal portion can be supported with a core support (for example, a removable core wire) disposed within an axially oriented lumen of the contraceptive device. Preferably, the distal portion will flex laterally to track through the uterotubal junction so that the contraceptive device is positioned across the muscular lumen narrowing adjacent of the uterotubal junction. A distal ball tip having a diameter in a range from about 0.020 inches to 0.050 inches can help avoid perforation and facilitate tubal navigation.
In another aspect, the invention provides a contraceptive method comprising inserting a contraceptive device distally into an ostium of a fallopian tube. A proximal portion of the inserted contraceptive device is uncovered by withdrawing a sheath from around the proximal portion. An expandable structure of the proximal portion is maintained in a small profile configuration during the uncovering step so as to avoid restricting movement of the sheath while the sheath is withdrawn. The uncovered expandable structure is radially expanded to a large profile configuration so as to affix the contraceptive device within the ostium. The uncovered contraceptive device is released so that the contraceptive device inhibits conception.
Preferably, the expandable portion is maintained in the small profile configuration using a restraining force or torque. This restraint can be transmitted proximally using a first elongate body and a second elongate body. Typically, the first and second elongate bodies sustain a wind-down torque on the expandable structure. The expandable structure can be expanded by actuating the proximal handle so as to rotationally and/or axially release a proximal end of the elongate bodies relative to each other.
In another aspect, the invention provides a contraceptive system comprising an intrafallopian contraceptive device having a proximal portion adjacent a proximal end and a distal portion adjacent a distal end. The distal portion has a flexibility suitable to function as a guidewire. A sheath is releasably secured over the proximal portion of the contraceptive device so that the distal portion of the contraceptive device remains exposed when the contraceptive device and sheath are inserted transcervically into an ostium of the fallopian tube. A first elongate body extends from a proximal end distally into detachable engagement with the contraceptive device for withdrawing the sheath from around the inserted contraceptive device.
In yet another aspect, the invention provides a contraceptive kit comprising a contraceptive device and instructions for deploying the contraceptive device. The instructions describe the method steps of guiding the contraceptive device into an ostium of a fallopian tube with a distal portion of the contraceptive device. The instructions also describe uncovering a proximal portion of the contraceptive device so that the proximal portion can restrain the contraceptive device within the ostium.